Biofiltration Media Optimization

Project summary
Biofiltration has become common in Minnesota’s urban landscape because it is one of the
most robust stormwater treatment practices available to designers. Stormwater professionals and
practitioners, however, still face challenging decisions while designing these practices and often feel
as if they are guessing when selecting media components and designing these practices. In particular,
the most commonly used and recommended biofiltration media mixes have been shown to export
phosphate, potentially contributing to water quality impairments. This increases environmental risk
and uncertainty when attempting to implement TMDL recommendations. Thus, the objectives of this
research are to 1) identify which local and sustainable biofiltration media are effective for
filtration rate, supporting plant growth and microbial function, and that do not release phosphate, and
2) document local sources, simple tests or metrics, and/or design specifications that can be used
by practitioners to reliably and repeatably obtain a biofiltration practice that functions as expected.
The communication, outreach, and technology transfer plan includes updates to the
Minnesota Stormwater Manual and the Minimal Impact Design Standards (MIDS) calculator,
webinars, videos, and articles in widely distributed newsletters. Results will also be incorporated into
existing or new professional training, continuing education, and certification for stormwater
professionals and practitioners. This study will fill the knowledge gap of the best available
biofiltration media components that can be locally sourced in Minnesota and accurately specified.
This will empower practitioners with the confidence to design biofiltration practices with the best
available knowledge and understanding of media components in Minnesota.

2019 Mid-Project Presentation .pdf

Project Staff: 

Project Leader (Principal Investigator, Primary Point of Contact):
Andy Erickson, P.E., Ph.D., Research Associate, St. Anthony Falls Laboratory, University of
Minnesota, eric0706@umn.edu, 612-239-2046
St. Anthony Falls Laboratory:

Jessica Kozarek (Co-Lead), Ph.D., Research Associate, jkozarek@umn.edu, 612-624-4679
Aaron Ketchmark, Researcher II, ketch056@umn.edu
Barbara Heitkamp, M.S., Communications Specialist, bkb0811@umn.edu, 612-626-6166
Project Co-Lead: Mike Isensee, CPESC, Administrator, Middle St. Croix Watershed Management
Organization; Watershed Specialist, Washington Conservation District, misensee@mnwcd.org,
651-330-8220 Ext. 22
Minnesota Pollution Control Agency:
Mike Trojan, Ph.D., Senior Hydrologist, mike.trojan@state.mn.us, 651-757-2790
David Fairbairn, Ph.D., Research Scientist, david.fairbairn@state.mn.us, 651-757-2659
Extension Educator: John Chapman, Ph.D.; Assistant Professor, University of Minnesota Dept. of
Bioproducts and Biosystems Engineering, chapm155@umn.edu, 612-626-4857
Project Team Member: Erin Anderson Wenz, ENV SP, PE, Vice President, Senior Water Resources
Engineer, eandersonwenz@barr.com, 952-832-2805

Project Duration: 

January 2019-June2020

Objective: 

The objectives of this research are to 1) identify which local and sustainable
biofiltration media are effective for filtration rate, supporting plant growth and microbial
function, and that do not release phosphate, and 2) document local sources, simple tests or
metrics, and/or design specifications that can be used by practitioners to reliably and
repeatably obtain a biofiltration practice that functions as expected.